Number analogy section deals with two types of questions:
I. Choosing a similarly related pair as the given number pair on the basis of the relation between the numbers in each pair.
II. Choosing a number similar to a group of numbers on the basis of certain common properties that they possess.
3 : 11 : : 7 : ?
Clearly, 32 + 2 = 11.
Now, 72 + 2 = 51.
So, If the first number is x, the second number is x2 + 2.
Thus, the relationship is x : x2 + 2.
Hence, the answer us (d) 51.